Type III protein translocase: HrcN is a peripheral ATPase that is activated by oligomerization (Journal article)

Pozidis, C./ Chalkiadaki, A./ Gomez-Serrano, A./ Stahlberg, H./ Brown, I./ Tampakaki, A. P./ Lustig, A./ Sianidis, G./ Politou, A. S./ Engel, A./ Panopoulos, N. J./ Mansfield, J./ Pugsley, A. P./ Karamanou, S./ Economou, A.


Type III protein secretion (TTS) is catalyzed by translocases that span both membranes of Gram-negative bacteria. A hydrophilic TTS component homologous to F1/V1-ATPases is ubiquitous and essential for secretion. We show that hrcN encodes the putative TTS ATPase of Pseudomonas syringae pathovar phaseolicola and that HrcN is a peripheral protein that assembles in clusters at the membrane. A decahistidinyl HrcN derivative was overexpressed in Escherichia coli and purified to homogeneity in a folded state. Hydrodynamic analysis, cross-linking, and electron microscopy revealed four distinct HrcN forms: I, 48 kDa (monomer); II, approximately 300 kDa (putative hexamer); III, 575 kDa (dodecamer); and IV, approximately 3.5 MDa. Form III is the predominant form of HrcN at the membrane, and its ATPase activity is dramatically stimulated (>700-fold) over the basal activity of Form I. We propose that TTS ATPases catalyze protein translocation as activated homo-oligomers at the plasma membrane.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικής
Keywords: Adenosine Triphosphatases/*chemistry/*physiology,Amino Acid Sequence,Bacterial Proteins/*chemistry,Cell Membrane/enzymology/metabolism,Chromatography,Circular Dichroism,Cross-Linking Reagents/pharmacology,Detergents/pharmacology,Dose-Response Relationship, Drug,Escherichia coli/metabolism,Hydrogen-Ion Concentration,Hydrolysis,Ions,Kinetics,Membrane Transport Proteins/*chemistry/*physiology,Microscopy, Electron,Molecular Sequence Data,Plasmids/metabolism,Protein Conformation,Protein Folding,Protein Structure, Secondary,Protein Structure, Tertiary,Protein Transport,Pseudomonas/*enzymology,Subcellular Fractions,Temperature,Water/metabolism
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/19643
ISSN: 0021-9258
Link: http://www.ncbi.nlm.nih.gov/pubmed/12734178
http://www.jbc.org/content/278/28/25816.full.pdf
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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